The Question:

Which U.S. state has the largest active volcano?

The Answer:

Hawaii's Mauna
Loa is not only the largest active volcano in the country, but the
largest in the world.

Rising 13,680 feet into the sky, Mauna Loa's appearance above
sea level is only a part of the story. Below the surface, Mauna Loa is
a marine giant, depressing the sea floor an additional 26,000 feet and
measuring about 56,000 feet from its base to summit.

In addition to being the world's biggest, it is also one of the
world's most active. Its most recent eruption was in 1984.